Opening of the 9/11 Memorial Museum

Tim Sloan / AFP

The American flag flies from a crane above Ground Zero during a memorial service at the site of the destroyed World Trade Center in November 2001. The service, attended by President George W. Bush, was held in honor of the foreign nationals who perished in the terrorist attacks on Sept. 11, 2001.

The American flag flies from a crane above Ground Zero during a memorial service at the site of the destroyed World Trade Center in November 2001. The service, attended by President George W. Bush, was held in honor of the foreign nationals who perished in the terrorist attacks on Sept. 11, 2001. (Tim Sloan / AFP)

The American flag flies from a crane above Ground Zero during a memorial service at the site of the destroyed World Trade Center in November 2001. The service, attended by President George W. Bush, was held in honor of the foreign nationals who perished in the terrorist attacks on Sept. 11, 2001.